668998 has 16 divisors (see below), whose sum is σ = 1119744. Its totient is φ = 297160.

The previous prime is 668989. The next prime is 668999. The reversal of 668998 is 899866.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (668999) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 711 + ... + 1357.

It is an arithmetic number, because the mean of its divisors is an integer number (69984).

2⁶⁶⁸⁹⁹⁸ is an apocalyptic number.

668998 is a deficient number, since it is larger than the sum of its proper divisors (450746).

668998 is a wasteful number, since it uses less digits than its factorization.

668998 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 707.

The product of its digits is 186624, while the sum is 46.

The square root of 668998 is about 817.9229792590. The cubic root of 668998 is about 87.4597583663.

The spelling of 668998 in words is "six hundred sixty-eight thousand, nine hundred ninety-eight".